This invention relates to tooling appropriate for use at the end of a robot arm used in a molding process. More particularly, this invention relates to using a robot to introduce an insert into a mold so that the insert can be integrated into the molded article.
Molding processes, such as an injection molding process, are commonly used for molding articles from moldable plastic material. The apparatus used to carry out the molding process generally comprises two mold surfacesxe2x80x94a core mold half and a cavity mold half The mold halves are brought together and charged with a moldable material. After applying heat and pressure to mold the article, the mold halves are separated for removal of the completed article. Robots are often used in molding operations to remove the molded articles after the product is molded. The robot typically uses either a grasping technique or a suction apparatus to remove the molded article.
Often it is desirable to place a foreign substance, i.e., a material different from the moldable material, into the mold so that the foreign substance can be molded into the article during the molding process. These foreign substances, referred to as molding inserts, become part of the final molded product. Alternatively, a detail of the insert is left on the plastic part. The insert can be metallic as well as cloth or plastic, and can be in the form of a threaded core, a retaining ring, or a film. The insert can be, for example, a threaded metal sleeve to become molded into the neck of a molded plastic bottle. Another example of an insert is a label containing such information as product identification, operating instructions, bar codes, safety information such as warning labels, and decorations, with the label being integrally molded into the surface of the molded article. Applying labels as inserts to molded articles is particularly advantageous because of the toughness of the bond between the label and the molded article. Frequently, these inserts are placed by hand into the mold between cycles. It would be advantageous if an automated system could be developed.
Miller in U.S. Pat. No. 5,527,173 discloses an injection molding system that includes a carrier plate or rack 20 for receiving completed articles. The rack is positionable between the cavity and core mold halves after the mold cycle. Schad et al. in U.S. Pat. No. 5,582,845 discloses an injection molding system where a robot uses a vacuum system to grasp mold inserts for insertion into molds. The robot also removes the molded articles (preforms) from the molds. A positive air pressure system assists in removal of the molded articles from the robot at the appropriate time.
The above objects as well as other objects not specifically enumerated are achieved by apparatus for molding articles from moldable material in a mold comprising end of arm tooling for an articulated robot arm associated with the mold, where the end of arm tooling includes an insert transfer member mounted on the end of the articulated robot arm. The insert transfer member has an insert holder for gripping the insert. The apparatus also includes a charger for generating an electric field that causes the insert to adhere onto a surface of the mold.
According to the present invention, there is also provided apparatus for molding articles from moldable material in a mold comprising end of arm tooling for an articulated robot arm associated with the mold. The end of arm tooling includes an insert transfer member mounted on the end of the articulated robot arm. The insert transfer member has a vacuum-assisted insert holder supplied with a source of vacuum for gripping the insert. The apparatus also includes a charger for generating an electric field that causes the insert to adhere onto a surface of the mold. The charger includes a wand that is positioned outside the mold.
In a particular embodiment of the invention the insert holder includes suction cups for applying a vacuum to the insert, and the apparatus further includes an article removal assembly mounted on the end of arm tooling for removing molded articles from the mold.
According to this invention there is also provided a method of molding articles from moldable material comprising opening a mold having a mold cavity, and introducing end of arm tooling on a robot arm into the mold cavity, where the end of arm tooling is gripping an insert. An electric field that causes the insert to adhere onto a surface of the mold is generated. The end of arm tooling is removed from the mold;. The mold is charged and closed for molding. The end of arm tooling comprises an insert transfer member mounted on the end of the articulated robot arm. The insert transfer member has an insert holder for gripping the insert.
In a particular embodiment of the invention, the insert holder positions the insert in contact with the surface of the mold prior to the step of generating the electric field.
In another specific embodiment of the invention, the step of generating the electric field occurs prior to the introduction of the insert into the mold. The insert holder and insert are moved through the electric field to charge the insert prior to the introduction of the insert into the mold. The end of arm tooling grips the insert with a vacuum during the step of introducing the insert into the mold. The insert holder then positions the insert in contact with the surface of the mold. Then the vacuum is removed, thereby releasing the grip of the insert holder on the insert.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.